Improvement in portable derricks



W. 000KB. Portable Derrick.

No. 20!,998. Patented April 2, 1878.

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UNITED STAT s PATENTOF IoE.

WATTS OOOKE, OF rAT RsoN, NEW JERSEY.

IMPROVEMENT IN PORTABLE DERRICKS.

Specification forming part of Letters Patent N0. 201,998, dated April 2,1878; application filed Q I March 11, 1878.

To all whom it may concern:

Be it known that I, WATTS OOOKE,'Of Pat erson, Passaic county, in. theState of New Jersey, have invented certain new and useful Improvementsrelating to Portable Derricks, of which the following is aspecification:

My improved derrick is adapted for moving the load laterally withincertain limits without swinging or moving any of the rigid parts. Thereare two separate jibs or rigid arms extending near each other, andpreferably wider at the base, so as to be, in fact, a forked jib, withhoisting-tackle connected to each of the arms, so that by varying theaction on the two hoisting-ropes the mass lifted may be suspended eithermidway between or partly or entirely over toward either of the jibs.

The device is especially useful in hoisting tall objects, astelegraph-poles, or the uprights of trestle-work, bridges, or elevatedrailroads.

The accompanying drawings form a part of this specification, andrepresent what I consider the'best means of carrying out the invention.

Figure 1 is a side elevation, and Fig. 2 is a front elevation.

Similar letters of reference indicate like par ts in both the figures.

A is a stout frame-work, supported by wheels A, one pair of which iscapable of swiveling, for convenience of manipulation, and may beequipped with the ordinary tongue and whiffletrees, for convenientmovement by horses.

B and B are the two jibs, connected rigidly together near the base. butheld a considerable distance apart at the top. Each is of i triangularform, so that the two jibs constitute a forked piece turning on stouteyes or hinges I), supported 011 the framing A. The compound jib B Balso carries two windlasses, M M with suitable gearing for driving them,which operate two ropes, m m which run respectively oversupporting-sheaves in the tops of their corresponding arms or jibs B BThere may be a double or triple block suspended to the top of each jib,with a corresponding block below, to give a strong purchase for lifting.I have so represented it, the compound tackle beingrepresentedby J J Inthe use of my derrick both the tackles J and J 2 are engaged with theobject to be raised,

' siderable.

and both the windlasses M M being operated at an equal rate, the weight,marked K, is lifted in the central line between B B but both windlassesbeing operated independently. lf one is worked ahead of the other, so asto shorten its tackle, the mass'or weight is moved nearer to that arm orjib. I have represented it as having the tackle J 2 shortened the most.

Each jib is formed of two principal parts, extending up and down, and ofa series of diagonal or other suitable light braces connecting themlaterally.

' It is obvious that when the weight is first started to be lifted froma point at the level of the wheels A, or lower, the strain will bemainly on the outer and more perfectly upright parts; but there areconditions under which the strain tending to draw the upper ends of thejibs toward each other is very con This especially obtains when a heavymass has been raised nearly to the top of the jibs, and is supportedmidway between them.

It is obviously important, in order to raise telegraph-poles and thelike, that there shall be no direct brace across between the jibs.

It will be understood that the framing A may be loaded with any requiredweight at or near the end opposite the jibs 13 13 to enable the framingto resist the tilting strain induced by the overhanging jibs whenlifting a heavy load.

In case the windlasses are operated by steam,

' the boiler may be placed on or near the other end of the framing.

Whether or not the framing is heavilyloaded, I construct triangularfixed frames or uprights A at the end of the framing A, opposite to thecompound jib, and connect them by guys G G to the upper ends of therespective jibs B B Operating these guys by hand or by the windlasses,the inclination of the jibs B B may be changed Within wide limits.

H H are rigid braces pivoted to the sides of the jibs, as shown, andadapted to be se cured to the sides of the framing A in variouspositions by nuts fitting on stationary bolts set in the framing. Theremay be a series of holes adapted to receive the bolt in different holesas the inclination of the compound jibis changed; but the slotsrepresented give the important advantage that on simply slackenin g thenuts '5 and relaxing or tightening the guys G G the connection of thebraces H H will adjust themselves without requiring any attention. Afterthe jibs have been adjusted to the proper inclination the nuts 6 aretightened, and, the guys G G being preferably set taut, the derrick isready to be operated.

Modifications may be made. I can adapt the wheels A to run on arailroad-track. The framing A may be of wood, and flat instead of raisedat the end opposite the sheaves; but I have represented what I esteemthe preferable construction of all the parts.

I esteem it important that my compound jibs shall offer no obstructionsbetween the two forks to prevent the swinging of any load, pole, orother object of any form. The two parts may be mounted independently onthe framing A, so that one may be set at a different anglefrom theother; buttheincreased strength due to my constructing them in one atand near the base more than compensates for any advantages due to suchcapacity.

I claim as my invention- The portable derrick described, having, incombination with the frame or carriage A and wheels A, the forked orcompound jibs B B, with independent windlasses M M and connecting-tackle J J, adapted to serve as and for the purposes hereinspecified.

In testimony whereof I have hereunto set my name in presence of twosubscribing witnesses.

WATTS OOOKE.

Witnesses A. H. GENTNER, W. L; BENNEM.

